JavaScript API Reference

PDF Oxide provides WebAssembly bindings for JavaScript and TypeScript. The npm package pdf-oxide-wasm works in Node.js, browsers, bundlers, Deno, and Cloudflare Workers.

npm install pdf-oxide-wasm

Multi-target packaging (v0.3.38)

pdf-oxide-wasm now ships three builds side by side with package.json conditional exports. Pick the subpath that matches your runtime — the auto-routed top-level import also resolves correctly through the exports field for most environments.

Subpath	Target
pdf-oxide-wasm/nodejs	Node.js (CommonJS + ESM)
pdf-oxide-wasm/bundler	Vite, webpack, Rollup, esbuild, Bun
pdf-oxide-wasm/web	Browsers, Deno, Cloudflare Workers

// Node.js
import { WasmPdfDocument } from "pdf-oxide-wasm/nodejs";

// Vite / webpack / Rollup
import init, { WasmPdfDocument } from "pdf-oxide-wasm/bundler";
await init();

// Browsers / Deno / Workers
import init, { WasmPdfDocument } from "pdf-oxide-wasm/web";
await init();

This fixes the ReferenceError: Can't find variable: __dirname thrown under browser bundlers prior to v0.3.38.

For the Rust API, see the Rust API Reference. For the Python API, see the Python API Reference. For type details, see Types & Enums.

---

WasmPdfDocument

The primary class for opening, extracting, editing, and saving PDFs.

import { WasmPdfDocument } from "pdf-oxide-wasm";

Constructor

new WasmPdfDocument(data)

Load a PDF document from raw bytes.

Parameter	Type	Description
data	Uint8Array	The PDF file contents

Throws: Error if the PDF is invalid or cannot be parsed.

const bytes = new Uint8Array(readFileSync("document.pdf"));
const doc = new WasmPdfDocument(bytes);

---

Core Read-Only

pageCount() -> number

Get the number of pages in the document.

version() -> Uint8Array

Get the PDF version as [major, minor].

const [major, minor] = doc.version();
console.log(`PDF ${major}.${minor}`);

authenticate(password) -> boolean

Decrypt an encrypted PDF. Returns true if authentication succeeded.

Parameter	Type	Description
password	string	The password string

hasStructureTree() -> boolean

Check if the document is a Tagged PDF with a structure tree.

---

Text Extraction

extractText(pageIndex) -> string

Extract plain text from a single page.

Parameter	Type	Description
pageIndex	number	Zero-based page number

const text = doc.extractText(0);

extractAllText() -> string

Extract plain text from all pages, separated by form feed characters.

extractChars(pageIndex) -> Array

Extract individual characters with precise positioning and font metadata.

Parameter	Type	Description
pageIndex	number	Zero-based page number

Returns: Array of objects with fields:

Field	Type	Description
char	string	The character
bbox	{x, y, width, height}	Bounding box
fontName	string	Font name
fontSize	number	Font size in points
fontWeight	string	Weight (Normal, Bold, etc.)
isItalic	boolean	Italic flag
color	{r, g, b}	RGB color (0.0–1.0)

const chars = doc.extractChars(0);
for (const c of chars) {
  console.log(`'${c.char}' at (${c.bbox.x}, ${c.bbox.y})`);
}

extractPageText(pageIndex) -> object

Get spans, characters, and page dimensions from a single extraction pass. More efficient than calling extractSpans() + extractChars() separately.

Parameter	Type	Description
pageIndex	number	Zero-based page number

Returns: An object with fields:

Field	Type	Description
spans	Array	Array of span objects
chars	Array	Array of character objects
pageWidth	number	Page width in PDF points
pageHeight	number	Page height in PDF points
text	string	Full text content

const result = doc.extractPageText(0);
console.log(`Page: ${result.pageWidth}x${result.pageHeight} pt`);
for (const span of result.spans) {
  console.log(`'${span.text}' font=${span.fontName} size=${span.fontSize}`);
}

extractSpans(pageIndex, config?, readingOrder?) -> Array

Extract styled text spans with font metadata. Pass "column_aware" as readingOrder for multi-column PDFs.

Parameter	Type	Description
pageIndex	number	Zero-based page number
config	object | undefined	Optional span merging config
readingOrder	string | undefined	Reading order: "column_aware" or undefined for default

Returns: Array of objects with fields:

Field	Type	Description
text	string	The text content
bbox	{x, y, width, height}	Bounding box
fontName	string	Font name
fontSize	number	Font size in points
fontWeight	string	Weight (Normal, Bold, etc.)
isItalic	boolean	Italic flag
isMonospace	boolean	Whether the font is fixed-width
charWidths	number[]	Per-glyph advance widths
color	{r, g, b}	RGB color (0.0–1.0)

const spans = doc.extractSpans(0);
for (const span of spans) {
  console.log(`"${span.text}" size=${span.fontSize}`);
}

---

Format Conversion

toMarkdown(pageIndex, detectHeadings?, includeImages?, includeFormFields?) -> string

Convert a single page to Markdown.

Parameter	Type	Default	Description
pageIndex	number	–	Zero-based page number
detectHeadings	boolean	true	Detect headings from font size
includeImages	boolean	true	Include images
includeFormFields	boolean	true	Include form field values

toMarkdownAll(detectHeadings?, includeImages?, includeFormFields?) -> string

Convert all pages to Markdown.

toHtml(pageIndex, preserveLayout?, detectHeadings?, includeFormFields?) -> string

Convert a single page to HTML.

Parameter	Type	Default	Description
pageIndex	number	–	Zero-based page number
preserveLayout	boolean	false	Preserve visual layout
detectHeadings	boolean	true	Detect headings
includeFormFields	boolean	true	Include form field values

toHtmlAll(preserveLayout?, detectHeadings?, includeFormFields?) -> string

Convert all pages to HTML.

toPlainText(pageIndex) -> string

Convert a single page to plain text.

toPlainTextAll() -> string

Convert all pages to plain text.

---

Search

search(pattern, caseInsensitive?, literal?, wholeWord?, maxResults?) -> Array

Search for text across all pages.

Parameter	Type	Default	Description
pattern	string	–	Search pattern (string or regex)
caseInsensitive	boolean	false	Case-insensitive search
literal	boolean	false	Treat pattern as literal string
wholeWord	boolean	false	Match whole words only
maxResults	number	–	Maximum results to return

Returns: Array of objects with fields:

Field	Type	Description
page	number	Page number
text	string	Matched text
bbox	object	Bounding box
startIndex	number	Start index in page text
endIndex	number	End index in page text

searchPage(pageIndex, pattern, caseInsensitive?, literal?, wholeWord?, maxResults?) -> Array

Search for text within a single page.

---

Image Info

extractImages(pageIndex) -> Array

Get image metadata for a page.

Field	Type	Description
width	number	Image width in pixels
height	number	Image height in pixels
colorSpace	string	Color space (e.g. DeviceRGB)
bitsPerComponent	number	Bits per color channel
bbox	object	Position on page

extractImageBytes(pageIndex) -> Array

Extract raw image bytes from a page. Returns an array of objects:

Field	Type	Description
width	number	Image width in pixels
height	number	Image height in pixels
data	Uint8Array	Raw image bytes
format	string	Image format

pageImages(pageIndex) -> Array

Get image names and bounds for positioning operations.

Field	Type	Description
name	string	XObject name
bounds	number[]	[x, y, width, height]
matrix	number[]	Transform matrix [a, b, c, d, e, f]

---

Document Structure

getOutline() -> Array | null

Get document bookmarks / table of contents. Returns null if no outline exists.

getAnnotations(pageIndex) -> Array

Get annotation metadata (type, rect, contents, etc.) for a page.

extractPaths(pageIndex) -> Array

Get vector paths (lines, curves, shapes) from a page.

pageLabels() -> Array

Get page label ranges. Returns an array of objects:

Field	Type	Description
startPage	number	First page in this range
style	string	Numbering style
prefix	string	Label prefix
startValue	number	Starting number

xmpMetadata() -> object | null

Get XMP metadata. Returns null if not present. Object fields include:

Field	Type	Description
dcTitle	string | null	Document title
dcCreator	string[] | null	Creator list
dcDescription	string | null	Description
xmpCreatorTool	string | null	Creator tool
xmpCreateDate	string | null	Creation date
xmpModifyDate	string | null	Modification date
pdfProducer	string | null	PDF producer

---

Form Fields

getFormFields() -> Array

Get all form fields with name, type, value, and flags.

Field	Type	Description
name	string	Field name
fieldType	string	Field type (text, checkbox, etc.)
value	string	Current value
flags	number	Field flags

const fields = doc.getFormFields();
for (const f of fields) {
  console.log(`${f.name} (${f.fieldType}) = ${f.value}`);
}

hasXfa() -> boolean

Check if the document contains XFA forms.

getFormFieldValue(name) -> any

Get a form field value by name. Returns a string, boolean, or null depending on the field type.

Parameter	Type	Description
name	string	Field name

setFormFieldValue(name, value) -> void

Set a form field value by name.

Parameter	Type	Description
name	string	Field name
value	string | boolean	New field value

exportFormData(format?) -> Uint8Array

Export form data as FDF (default) or XFDF.

Parameter	Type	Default	Description
format	string	"fdf"	Export format: "fdf" or "xfdf"

---

Editing

Metadata

Method	Parameters	Description
setTitle(title)	string	Set document title
setAuthor(author)	string	Set document author
setSubject(subject)	string	Set document subject
setKeywords(keywords)	string	Set document keywords

Page Rotation

Method	Parameters	Description
pageRotation(pageIndex)	number	Get current rotation (0, 90, 180, 270)
setPageRotation(pageIndex, degrees)	number, number	Set absolute rotation
rotatePage(pageIndex, degrees)	number, number	Add to current rotation
rotateAllPages(degrees)	number	Rotate all pages

Page Dimensions

Method	Parameters	Description
pageMediaBox(pageIndex)	number	Get MediaBox [llx, lly, urx, ury]
setPageMediaBox(pageIndex, llx, lly, urx, ury)	number, ...	Set MediaBox
pageCropBox(pageIndex)	number	Get CropBox (may be null)
setPageCropBox(pageIndex, llx, lly, urx, ury)	number, ...	Set CropBox
cropMargins(left, right, top, bottom)	number, ...	Crop all page margins

Erase / Whiteout

Method	Parameters	Description
eraseRegion(pageIndex, llx, lly, urx, ury)	number, ...	Erase a region
eraseRegions(pageIndex, rects)	number, Float32Array	Erase multiple regions
clearEraseRegions(pageIndex)	number	Clear pending erases

Annotations & Redaction

Method	Parameters	Description
flattenPageAnnotations(pageIndex)	number	Flatten annotations on page
flattenAllAnnotations()	–	Flatten all annotations
applyPageRedactions(pageIndex)	number	Apply redactions on page
applyAllRedactions()	–	Apply all redactions

Form Flattening

Method	Parameters	Description
flattenForms()	–	Flatten all form fields into page content
flattenFormsOnPage(pageIndex)	number	Flatten forms on a specific page

Merge & Embed

mergeFrom(data) -> number

Merge pages from another PDF. Returns the number of pages merged.

Parameter	Type	Description
data	Uint8Array	The source PDF file bytes

embedFile(name, data) -> void

Attach a file to the PDF.

Parameter	Type	Description
name	string	Filename for the attachment
data	Uint8Array	File contents

Image Manipulation

Method	Parameters	Description
repositionImage(pageIndex, name, x, y)	number, string, number, number	Move image
resizeImage(pageIndex, name, w, h)	number, string, number, number	Resize image
setImageBounds(pageIndex, name, x, y, w, h)	number, string, ...	Set image bounds

Rendering

Method	Parameters	Returns	Description
renderPage(pageIndex, dpi?)	number, number	Uint8Array	Render a page to PNG bytes
flattenToImages(dpi?)	number	Uint8Array	Flatten all pages to image-based PDF

---

Save

save() -> Uint8Array

Save the edited PDF as bytes. saveToBytes() is available as an alias.

saveEncryptedToBytes(password, ownerPassword?, allowPrint?, allowCopy?, allowModify?, allowAnnotate?) -> Uint8Array

Save with AES-256 encryption.

Parameter	Type	Default	Description
password	string	–	User password
ownerPassword	string	user password	Owner password
allowPrint	boolean	true	Allow printing
allowCopy	boolean	true	Allow copying
allowModify	boolean	false	Allow modification
allowAnnotate	boolean	true	Allow annotations

free()

Release WASM memory. Always call this when done with the document.

---

WasmPdf

Factory class for creating new PDFs.

import { WasmPdf } from "pdf-oxide-wasm";

Static Methods

WasmPdf.fromMarkdown(content, title?, author?) -> WasmPdf

Create a PDF from Markdown text.

Parameter	Type	Default	Description
content	string	–	Markdown content
title	string	–	Document title
author	string	–	Document author

WasmPdf.fromHtml(content, title?, author?) -> WasmPdf

Create a PDF from HTML.

WasmPdf.fromText(content, title?, author?) -> WasmPdf

Create a PDF from plain text.

WasmPdf.fromImageBytes(data) -> WasmPdf

Create a single-page PDF from image bytes.

Parameter	Type	Description
data	Uint8Array	Image file bytes (JPEG, PNG)

WasmPdf.fromMultipleImageBytes(imagesArray) -> WasmPdf

Create a multi-page PDF from multiple images, one page per image.

Parameter	Type	Description
imagesArray	Uint8Array[]	Array of image file bytes

Instance Methods

toBytes() -> Uint8Array

Get the PDF as bytes.

size -> number

PDF size in bytes (readonly property).

const pdf = WasmPdf.fromMarkdown("# Hello World\n\nThis is a PDF.");
console.log(`PDF size: ${pdf.size} bytes`);
writeFileSync("output.pdf", pdf.toBytes());

---

Feature Availability

Some features require native dependencies and are not available in WebAssembly:

Feature	WASM	Notes
Text extraction	Yes	Full support
Structured extraction	Yes	Chars, spans
PDF creation	Yes	Markdown, HTML, text, images
PDF editing	Yes	Metadata, rotation, dimensions, erase
Form fields	Yes	Read, write, export, flatten
Search	Yes	Full regex support
Encryption	Yes	AES-256 read and write
Annotations	Yes	Read, flatten, redact
Merge PDFs	Yes	Merge pages from another PDF
Embedded files	Yes	Attach files to PDFs
Page labels	Yes	Read page label ranges
XMP metadata	Yes	Read XMP metadata
OCR	No	Requires native ONNX Runtime
Digital signatures	No	Requires native crypto libraries
Page rendering	No	Requires native tiny-skia
Barcodes	No	Requires native rendering
Office conversion	No	Requires native LibreOffice

---

Error Handling

All methods that can fail throw JavaScript Error objects:

try {
  const doc = new WasmPdfDocument(new Uint8Array([0, 1, 2]));
} catch (e) {
  console.error(`Failed to open: ${e.message}`);
}

---

TypeScript

Full type definitions are included in the package:

import { WasmPdfDocument, WasmPdf } from "pdf-oxide-wasm";

const doc: WasmPdfDocument = new WasmPdfDocument(bytes);
const text: string = doc.extractText(0);
const pdf: WasmPdf = WasmPdf.fromMarkdown("# Hello");